The invention generally relates to valves for use in product-guiding plants. More specifically, the invention relates to a valve, comprising a housing, in which a closure member and a closure member seat are arranged. The closure member seat being provided on a cylindrical inner wall of a housing portion of the housing, wherein the closure member has a sealing element, which cooperates in a sealing manner with the closure member seat in a closed position of the closure member. The closure member is displaceable in the direction of a longitudinal axis of the housing between an open position, in which the sealing element is distanced from the closure member seat, and the closed position.
A valve of the type described in the introduction can be used for example in the food processing industry, but also in the chemical industry, in product-guiding processing plants.
A valve according to the invention can be designed as a single seat valve with just one closure member and just one closure member seat, as a double seat valve with two closure members and two closure member seats, or as a double sealing valve with a closure member with two sealing elements spaced in the direction of the longitudinal axis of the housing.
A valve of the type described in the introduction is generally used in a product-guiding processing plant to separate two pipelines from one another in the closed position of the closure member, such that no product can pass from the one pipeline into the other pipeline, or to interconnect the two pipelines in a product-guiding manner in the open position of the closure member. In the open position of the closure member, product flows from one pipeline, through the valve housing, past the closure member and closure member seat, and into the other pipeline.
Within the meaning of the present invention, “product” is not only understood to mean an end product, but also preliminary stages of products or components of products or ingredients, which are processed to form a finished product.
If such a product-guiding processing plant is used in a brewery for example, water, yeast, wort, green beer or finished beer for example may flow through the pipelines.
If such a product-guiding processing plant is used in a dairy for example, milk, fruit preparations, yoghurt, milk-based beverage preparations and the like may flow through the plant.
If the product-guiding processing plant is used in a facility, for example for producing finished soups and the like, products containing not only liquid, but also solid material, flow through the pipelines of the processing plant accordingly.
An example of a product-guiding processing plant in the chemical industry is a plant for producing paints or varnishes for example.
When operating a valve of the type described in the introduction in a product-guiding processing plant, it has been found that product residues may deposit on the cylindrical inner wall of the housing portion, in which the at least one closure member seat is provided. In particular when the valve is used in a product-guiding processing plant of a milk processing facility, it has been found that product residues that tend to harden in a gypseous manner and adhere relatively firmly to the inner wall of the cylindrical housing portion deposit on the cylindrical inner wall of the housing portion. When the closure member is transferred into the closed position, the sealing element may not be able to detach or push aside the product residues depending on the strength of the attachment of the product residues to the cylindrical inner wall of the housing portion, but instead the sealing element runs over the adhering product residues. As the sealing element is moved along the cylindrical inner wall of the housing portion, the sliding friction of the sealing element along the cylindrical inner wall of the housing portion thus increases disadvantageously, and the movement of the sealing element over the product residues disadvantageously leads to quicker wear of the sealing element. If the product residues are located in the region of the closure member seat, the sealing effect of the sealing element at the closure member seat is also reduced, and therefore the valve may exhibit leaks even when the sealing element is not yet worn.
With a known valve according to DE 10 2007 038 124 A1, no measures are taken to remedy this problem.